Fungicide



49 more it is quite well established that the Patented July 8, 1930UNITED STATES PATENT OFFICE FUN GICIDE No Drawing.

This invention relates to fungicides and more particularly to that typeemploying a sulphur base.

Many substances have heretofore been pro- 5 posed for use as fungicidesand insecticides. Of these perhaps the three more important groups arethose which use a copper, mercury orsulphur body. Mercury disinfectantsor fungicides present the disadvantage of relatively high cost; inaddition to this, these compounds are poisonous and hence subject theoperator to possible poisoning. Copper and sulphur compounds used forthis purpose have not been particularly eflica'cious because it has beenfound that their use has insured only a slight degree of control ofplant diseases. Of these two, the sulphur compounds appear to be thebest plant disinfectants to date.

At the present time both dust fungicides and liquid fungicides are beingused. The former appear to have a wider use, due in a large measure totheir greater economy. It is, however, generally conceded that theliquid spray is the most eflective for preventing plant diseases.

It is an object of my invention to rende dust fungicides moreefficacious.

It is a further object of my invention to improve sulphur fungicideswith no appreciable cost increase.

It appears to be doubtful that sulphur as V such possesses any greatutility as an insecticide or fungicide. Its effectiveness for thispurpose seems to depend on the fact that from it certain oxidationproducts are formed. It is now generally acceptedthat the fungicidalproperties of sulphur are due to the formation of polythionic acids."Furtherpentathionic acid is an active fungicidal agent.

It has been the practice heretofore to grind sulphur to a suitabledegree of fineness and to spray it as a dust or suspended in a liquidcarrier on the infected plants. In the presence of sunlight the sulphuris oxidized and polythionic acids are formed. This oxida- 50 tion isslow and necessarily dependent to a Application filed January 29.3 1927.Serial No. 162,940.,

large degree on climatic factors and especially to solar conditions.

I propose to so treat the sulphur that its effectiveness as a fungicidewill be more quickly initiated and will be less dependent on thevariable factors mentioned; I accomplish this by incorporating with thesulphur an active oxidizing agent. This treatment insures a more rapidoxidation of the sulphur and hence an early and complete formation ofthe pentathionic acid. In both laboratory and field experiments I findthat much better results are obtained with sulphur treated with anoxidizing agent than with sulphur which is subjected only to atmospheric oxidation. In field work, on sugar cane for example, the numberof infections per leaf was greatly reduced when treated with sulphurhaving incorporated in it an oxidizing agent. The use of this modifiedform of sulphur resulted in a greater degree of control than could beobtained by the use of the ordinary powdered sulphur.

I have found that both liquid and solid oxidizing agents may be used.Thus I have used a dust which consisted of one percent of powderedpotassium permanganate thoroughly incorported in ninety-nine per cent ofpowdered sulphur. This mixture is easily made, it being only necessaryto powder the permanganate crystals and to mix these with the sulphur.

I have also found that a very effective fungicidal mixture can beprepared by using one-fourth of one per cent of nitric acid withpowdered sulphur. Inthis case the nitric acid is atomized on the sulphurand the mass thoroughly mixed. For preparing this product any suitablenebulizer and mixer may be used.

To obtain the best results, the sulphur used should be very finelydivided. I have experimented with flowers of sulphur and obtainedpleasing results. .I find, however, that a better effect can be obtainedby using sulphur which will pass a two hundred to a three hundred meshscreen.

While a sulphur dust, for the reasons stated, is more economical than aliquid spray, it is to be understood that my invention is not limited tothis particular form. After incor orating the oxidizing agent I maysuspen the resulting powder in a neu- 'tral liquid carrier and apply itto the plants in this form. It will be appreciated also that I may atthe one time incorporate several oxidizing agents with the sulphur.

It is to be understood that the, examples given are not exhaustive.- Ihave described 10 active solid and liquidoxidizing agents to typify howagents of this class may be incorporated with the sulphur. It is-obviousthat other fluid and solid agents may be used; it is dpreferable,however, to use agents of consi erable activity such as those mentioned.

I claim:

1. A fungicidal, insecticidal and disinfecting product comprisingsulphur havin in-. corporated therein an oxidizing agent orm- 20 ingdirectly polythionic acids in the presence of atmos heric moisture.

2. A un 'cide comprising finely divided sulphur an an incorporatedoxidizing agent forming directly polyt-bionic acids in the :5 presenceof atmospheric moisture.

3. A potentiall reactive fungicidal mixture comprising ely dividedsulphur and a small amount of an oxidizing agent to accelerate theformation of polythionic acids. a0 4. A composition having potentialfungicidal and insecticidal properties comprising sulphur and otassiumperman anate to accelerate the ormation of polyt ionic acids.

5. A fungicidal and insecticidal composi- 85 tion comprising finelydivided sulphur and a suflicient amount of potassium permanganatestoinitiate the formation of polythionic aci 6. A fungicidal andinsecticidal composim tion comprising finely divided sulphur and afinely divided oxidizin agent suflicient to form directlypolythiomc'acids in the-presence of atmo heric moisture.

p 7. A fungicldal and insecticidal com osi- 45 tion comprising aproximately 99% ely divlde'd sulphur an approximately 1% of an oxidizingagent.

In testimony whereof I aflix m signature. HENRY ATHERT N LEE.

